A028565 Palindromes of form k*(k+7).
0, 8, 44, 494, 858, 49494, 445544, 819918, 4462644, 8853588, 8913198, 81099018, 441525144, 882060288, 8100990018, 44105250144, 49781418794, 85831713858, 447597795744, 810009900018, 889249942988, 4410052500144, 4450696960544, 4927434347294, 80512566521508, 81000099000018
Offset: 1
Links
- Michael S. Branicky, Table of n, a(n) for n = 1..49
- Patrick De Geest, Palindromic Quasipronics of the form n(n+x)
Programs
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Mathematica
Select[Table[k(k+7),{k,0,9000100}],PalindromeQ] (* Harvey P. Dale, Dec 17 2024 *) -
Python
from itertools import count, islice def ispal(n): s = str(n); return s == s[::-1] def agen(): for k in count(0): if ispal(k*(k+7)): yield k*(k+7) print(list(islice(agen(), 28))) # Michael S. Branicky, Jan 26 2022
Formula
Extensions
a(23) and beyond from Michael S. Branicky, Jan 26 2022